diff options
| -rw-r--r-- | core/java/android/service/persistentdata/PersistentDataBlockManager.java | 5 | ||||
| -rw-r--r-- | services/core/java/com/android/server/PersistentDataBlockService.java | 20 |
2 files changed, 19 insertions, 6 deletions
diff --git a/core/java/android/service/persistentdata/PersistentDataBlockManager.java b/core/java/android/service/persistentdata/PersistentDataBlockManager.java index 0ffdf68..10ffe84 100644 --- a/core/java/android/service/persistentdata/PersistentDataBlockManager.java +++ b/core/java/android/service/persistentdata/PersistentDataBlockManager.java @@ -54,6 +54,9 @@ public class PersistentDataBlockManager { * Returns the number of bytes written or -1 on error. If the block is too big * to fit on the partition, returns -MAX_BLOCK_SIZE. * + * {@link #wipe} will block any further {@link #write} operation until reboot, + * in which case -1 will be returned. + * * @param data the data to write */ public int write(byte[] data) { @@ -108,6 +111,8 @@ public class PersistentDataBlockManager { /** * Zeroes the previously written block in its entirety. Calling this method * will erase all data written to the persistent data partition. + * It will also prevent any further {@link #write} operation until reboot, + * in order to prevent a potential race condition. See b/30352311. */ public void wipe() { try { diff --git a/services/core/java/com/android/server/PersistentDataBlockService.java b/services/core/java/com/android/server/PersistentDataBlockService.java index 94316fe..32b183b 100644 --- a/services/core/java/com/android/server/PersistentDataBlockService.java +++ b/services/core/java/com/android/server/PersistentDataBlockService.java @@ -50,15 +50,14 @@ import java.util.Arrays; * This data will live across factory resets not initiated via the Settings UI. * When a device is factory reset through Settings this data is wiped. * - * Allows writing one block at a time. Namely, each time - * {@link android.service.persistentdata.IPersistentDataBlockService}.write(byte[] data) - * is called, it will overwite the data that was previously written on the block. + * Allows writing one block at a time. Namely, each time {@link IPersistentDataBlockService#write} + * is called, it will overwrite the data that was previously written on the block. * * Clients can query the size of the currently written block via - * {@link android.service.persistentdata.IPersistentDataBlockService}.getTotalDataSize(). + * {@link IPersistentDataBlockService#getDataBlockSize} * - * Clients can any number of bytes from the currently written block up to its total size by invoking - * {@link android.service.persistentdata.IPersistentDataBlockService}.read(byte[] data) + * Clients can read any number of bytes from the currently written block up to its total size by + * invoking {@link IPersistentDataBlockService#read} */ public class PersistentDataBlockService extends SystemService { private static final String TAG = PersistentDataBlockService.class.getSimpleName(); @@ -78,6 +77,7 @@ public class PersistentDataBlockService extends SystemService { private int mAllowedUid = -1; private long mBlockDeviceSize; + private boolean mIsWritable = true; public PersistentDataBlockService(Context context) { super(context); @@ -349,6 +349,11 @@ public class PersistentDataBlockService extends SystemService { headerAndData.put(data); synchronized (mLock) { + if (!mIsWritable) { + IoUtils.closeQuietly(outputStream); + return -1; + } + try { byte[] checksum = new byte[DIGEST_SIZE_BYTES]; outputStream.write(checksum, 0, DIGEST_SIZE_BYTES); @@ -423,6 +428,9 @@ public class PersistentDataBlockService extends SystemService { if (ret < 0) { Slog.e(TAG, "failed to wipe persistent partition"); + } else { + mIsWritable = false; + Slog.i(TAG, "persistent partition now wiped and unwritable"); } } } |